Prevalence of Unexplained Left Ventricular Hypertrophy by Cardiac Magnetic Resonance Imaging in MESA

The Diagnostic and Therapeutic Implications of Phenocopies and Mimics of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common myocardial disease defined by increased left ventricular wall thickness unexplained by loading conditions. HCM frequently is caused by pathogenic variants in sarcomeric protein genes, but several other syndromic, metabolic, infiltrative, and neuromuscular diseases can result in HCM phenocopies. This review summarizes the current understanding of these HCM mimics, highlighting their importance across the life course. The central role of a comprehensive, multiparametric diagnostic approach and the potential of precision medicine in tailoring treatment strategies are emphasized.

The Clinical Impact of SARS-CoV-2 on Hypertrophic Cardiomyopathy

BACKGROUND

This study aims to understand and describe the clinical impact of SARS-CoV-2 (COVID-19) infection in patients with Hypertrophic Cardiomyopathy (HCM).

METHODS

A data repository of over 6.6 million patients in a large metropolitan (Chicago IL) healthcare system was queried to identify adults with a history of HCM and COVID-19 infection between 2019 and 2021. Propensity score-matched analysis was performed based on age, sex, BMI, and elements of the cardiovascular history, including tobacco use, hypertension, hyperlipidemia, myocardial injury, and heart failure.

RESULTS

Individuals with HCM and COVID-19 infection had more total hospitalizations (41.6 v 23 per 100 persons, p < 0.01), more heart-failure-related hospitalizations (24.2 v 8.7 per 100-persons, p < 0.01), more non-ST elevation myocardial injury (NSTEMI) hospitalizations (8.6 v 4.6 per 100-persons, p < 0.01), and increased mortality (10.8 v 5 per 100-persons, p < 0.01) compared to HCM patients without a history of COVID-19 infection. Patients with HCM and COVID-19 were also noted to have a higher peak CRP when compared to those without prior COVID-19 (Inter-quartile range of 9.0-106.9 v 1.8-21.3, p < 0.01).

CONCLUSIONS

In patients with HCM, COVID-19 infection is associated with increased incidence of myocardial injury, increased number of total and heart-failure specific hospitalizations, and increased mortality.

Associations of Circulating Vascular Cell Adhesion Molecule-1 and Intercellular Adhesion Molecule-1 With Long-Term Cardiac Function

BACKGROUND

Although VCAM-1 (vascular cell adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1) have been associated with incident heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF), the associations of VCAM-1 and ICAM-1 with sensitive measures of cardiac structure/function are unclear. The objective of this study is to evaluate associations between VCAM-1, ICAM-1, and measures of cardiac structure and function as potential pathways through which cellular adhesion molecules promote HFpEF and AF risk.

METHODS AND RESULTS

In MESA (Multi-Ethnic Study of Atherosclerosis), we evaluated the associations of circulating VCAM-1 and ICAM-1 at examination 2 (2002-2004) with measures of cardiac structure/function on cardiac magnetic resonance imaging at examination 5 (2010-2011) after multivariable adjustment. Mediation analysis of left atrial (LA) strain on the association between VCAM-1 or ICAM-1 and AF or HFpEF was also performed. Overall, 2304 individuals (63±10 years; 47% men) with VCAM-1 or ICAM-1, cardiac magnetic resonance imaging, and covariate data were included in analysis. Higher VCAM-1 and ICAM-1 were associated with lower LA peak longitudinal strain and worse global circumferential left ventricular strain but were not associated with left ventricular myocardial scar or interstitial fibrosis. Lower LA peak longitudinal strain mediated 8% (95% CI, 2-30) of the relationship between VCAM-1 and HFpEF and 9% (95% CI, 2-21) of the relationship between VCAM-1 and AF.

CONCLUSIONS

Higher VCAM-1 and ICAM-1 were associated with lower LA function and left ventricular systolic function but were not associated with myocardial scar or interstitial fibrosis. VCAM-1 and ICAM-1 may promote HFpEF and AF risk through impaired LA reservoir function.

Identification of high-risk imaging features in hypertrophic cardiomyopathy using electrocardiography: A deep-learning approach

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) are at risk of sudden death, and individuals with ≥1 major risk markers are considered for primary prevention implantable cardioverter-defibrillators. Guidelines recommend cardiac magnetic resonance (CMR) imaging to identify high-risk imaging features. However, CMR imaging is resource intensive and is not widely accessible worldwide.

OBJECTIVE

The purpose of this study was to develop electrocardiogram (ECG) deep-learning (DL) models for the identification of patients with HCM and high-risk imaging features.

METHODS

Patients with HCM evaluated at Tufts Medical Center (N = 1930; Boston, MA) were used to develop ECG-DL models for the prediction of high-risk imaging features: systolic dysfunction, massive hypertrophy (≥30 mm), apical aneurysm, and extensive late gadolinium enhancement. ECG-DL models were externally validated in a cohort of patients with HCM from the Amrita Hospital HCM Center (N = 233; Kochi, India).

RESULTS

ECG-DL models reliably identified high-risk features (systolic dysfunction, massive hypertrophy, apical aneurysm, and extensive late gadolinium enhancement) during holdout testing (c-statistic 0.72, 0.83, 0.93, and 0.76) and external validation (c-statistic 0.71, 0.76, 0.91, and 0.68). A hypothetical screening strategy using echocardiography combined with ECG-DL-guided selective CMR use demonstrated a sensitivity of 97% for identifying patients with high-risk features while reducing the number of recommended CMRs by 61%. The negative predictive value with this screening strategy for the absence of high-risk features in patients without ECG-DL recommendation for CMR was 99.5%.

CONCLUSION

In HCM, novel ECG-DL models reliably identified patients with high-risk imaging features while offering the potential to reduce CMR testing requirements in underresourced areas.

Hypertrophic Cardiomyopathy-Advances in Imaging and Diagnostic Strategies

Hypertrophic cardiomyopathy (HCM) is the most important and prevalent cardiac disease in cats. Due to the highly variable nature of HCM, a multimodal approach including physical examination, genetic evaluation, cardiac biomarkers, and imaging are all essential elements to appropriate and timely diagnosis. These foundational elements are advancing rapidly in veterinary medicine. Newer biomarkers such as galectin-3 are currently being researched and advances in tissue speckle-tracking and contrast-enhanced echocardiography are readily available. Advanced imaging techniques, such as cardiac MRI, are providing previously unavailable information about myocardial fibrosis and paving the way for enhanced diagnostic capabilities and risk-stratification in cats with HCM.

Phenotyping heart failure by genetics and associated conditions

Heart failure is a highly heterogeneous disease, and genetic testing may allow phenotypic distinctions that are incremental to those obtainable from imaging. Advances in genetic testing have allowed for the identification of deleterious variants in patients with specific heart failure phenotypes (dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy), and many of these have specific treatment implications. The diagnostic yield of genetic testing in heart failure is modest, and many rare variants are associated with incomplete penetrance and variable expressivity. Environmental factors and co-morbidities have a large role in the heterogeneity of the heart failure phenotype. Future endeavours should concentrate on the cumulative impact of genetic polymorphisms in the development of heart failure.

The evolving paradigm and current perception of hypertrophic cardiomyopathy: Implications for management

Recent evidence from imaging and genetic screening studies has clearly shown that hypertrophic cardiomyopathy (HCM) is more common than initially perceived, emphasizing the need to reassess its associated clinical and social burden. While clinical and academic efforts have long been focused on stratification of arrhythmic risk and management of intraventricular obstruction, progression of cardiac dysfunction and heart failure-related complications have emerged as most relevant from the epidemiological standpoint, delineating a major unmet need. Furthermore, a broader perspective of our patients' needs has become central in the care of individuals with HCM, addressing issues that are not strictly clinical but equally important to their wellbeing, such as quality of life, athletic participation, lifestyle and reproductive choices and psychological adaptation to a chronic condition often detected at a young age. The appropriate evaluation and objective assessment of disease burden associated with HCM are increasingly relevant not only to management but also to trial design and evaluation of the efficacy of emerging, targeted treatments. In this review, we discuss the evolving perception of HCM prevalence and natural history, as well as recent acquisitions regarding its true, often under-appreciated socio-economic and clinical burden.

Inappropriate activation of the renin-angiotensin system improves cardiac tolerance to ischemia/reperfusion injury in rats with late angiotensin II-dependent hypertension

The aim of the study was to clarify the role of the interplay between hypertension and the renin-angiotensin system (RAS) in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. We hypothesized that in the late phase of hypertension with already developed signs of end-organ damage, inappropriate RAS activation could impair cardiac tolerance to I/R injury. Experiments were performed in male Cyp1a1-Ren-2 transgenic rats with inducible hypertension. The early phase of ANG II-dependent hypertension was induced by 5 days and the late phase by the 13 days dietary indole-3-carbinol (I3C) administration. Noninduced rats served as controls. Echocardiography and pressure-volume analysis were performed, angiotensins' levels were measured and cardiac tolerance to ischemia/reperfusion injury was studied. The infarct size was significantly reduced (by 50%) in 13 days I3C-induced hypertensive rats with marked cardiac hypertrophy, this reduction was abolished by losartan treatment. In the late phase of hypertension there are indications of a failing heart, mainly in reduced preload recruitable stroke work (PRSW), but only nonsignificant trends in worsening of some other parameters, showing that the myocardium is in a compensated phase. The influence of the RAS depends on the balance between the vasoconstrictive and the opposed vasodilatory axis. In the initial stage of hypertension, the vasodilatory axis of the RAS prevails, and with the development of hypertension the vasoconstrictive axis of the RAS becomes stronger. We observed a clear effect of AT1 receptor blockade on maximum pressure in left ventricle, cardiac hypertrophy and ANG II levels. In conclusion, we confirmed improved cardiac tolerance to I/R injury in hypertensive hypertrophied rats and showed that, in the late phase of hypertension, the myocardium is in a compensated phase.

Blood pressure measurement modalities and indexed left ventricular mass in men with low-risk hypertension confirmed by ambulatory monitoring

BACKGROUND

Blood pressure (BP) measurement modalities such as ambulatory monitoring (ABPM) and noninvasive central aortic systolic pressure (CASP), have been reported to improve prediction of hypertension-mediated organ damage (HMOD) compared with conventional clinic BP. However, clinic BP is often confounded by poor measurement technique and 'white-coat hypertension' (WCH). We compared prediction of cardiac MRI (cMRI)-derived left ventricular mass index (LVMI) by differing BP measurement modalities in young men with elevated BP, confirmed by ABPM.

METHODS

One hundred and forty-three treatment-naive men (<55 years) with hypertension confirmed by ABPM and no clinical evidence of HMOD or cardiovascular disease (37% with masked hypertension) were enrolled. Relationships between BP modalities and cMRI-LVMI were evaluated.

RESULTS

Men with higher LVMI (upper quintile) had higher clinic, central and ambulatory SBP compared with men with lower LVMI. Regression coefficients for SBP with LVMI did not differ across BP modalities ( r  = 0.32; 0.3; 0.31, for clinic SBP, CASP and 24-h ABPM, respectively, P  < 0.01 all). Prediction for high LVMI using receiver-operated curve analyses was similar between measurement modalities. No relationship between DBP and LVMI was seen across measurement modalities.

CONCLUSION

In younger men with hypertension confirmed by ABPM and low cardiovascular risk, clinic SBP and CASP, measured under research conditions, that is, with strict adherence to guideline recommendations, performs as well as ABPM in predicting LVMI. Prior reports of inferiority for clinic BP in predicting HMOD and potentially, clinical outcomes, may be due to poor measurement technique and/or failure to exclude WCH.

How common is hypertrophic cardiomyopathy… really?: Disease prevalence revisited 27 years after CARDIA

Hypertrophic cardiomyopathy (HCM) is a heterogeneous albeit treatable cardiac disease of variable severity, with the potential for heart failure, atrial fibrillation and arrhythmic sudden death, characterized by otherwise unexplained left ventricular (LV) hypertrophy and affecting all ages and races. Over the last 30 years, several studies have estimated the prevalence of HCM in the general population, employing echocardiography and cardiac magnetic resonance imaging (CMR), as well electronic health records and billing databases for clinical diagnosis. The estimated prevalence in the general population based on the disease phenotype of LV hypertrophy by imaging is 1:500 (0.2%). This prevalence was initially proposed in 1995 in the population-based CARDIA study employing echocardiography, and more recently confirmed by automated CMR analysis in the large UK Biobank cohort. The 1:500 prevalence appears most relevant to clinical assessment and management of HCM. These available data suggest that HCM is not a rare condition but likely underdiagnosed clinically and by extrapolation potentially affects about 700,000 Americans and possibly 15 million people worldwide.

T1 values and extracellular volume fraction in asymptomatic subjects: variations in left ventricular segments and correlation with cardiovascular risk factors

To evaluate variations in pre-contrast (preT1) and post-contrast (postT1) myocardial T1 values and extracellular volume fraction (ECV) according to left ventricular (LV) segments and to find correlations between them and cardiovascular risk factors. The 233 asymptomatic subjects (210 men, 23 women; aged 54.1 ± 6.0 years) underwent cardiac magnetic resonance imaging with preT1 and postT1 mapping on a 1.5-T scanner. T1 values and ECVs were evaluated according to LV segments, age, sex, and estimated glomerular filtration rate (eGFR). Based on the presence of hypertension (HTN) and diabetes mellitus (DM), subjects were subdivided into the control, HTN, DM, and HTN and DM (HTN-DM) groups. T1 values and ECV showed significant differences between septal and lateral segments at the mid-ventricular and basal levels (p ≤ 0.003). In subgroup analysis, the HTN-DM group showed a significantly higher ECV (0.260 ± 0.023) than the control (0.240 ± 0.021, p = 0.011) and HTN (0.241 ± 0.024, p = 0.041) groups. Overall postT1 and ECV of the LV had significant correlation with eGFR (r = 0.19, p = 0.038 for postT1; r =  − 0.23, p = 0.011 for ECV). Septal segments show higher preT1 and ECV but lower postT1 than lateral segments at the mid-ventricular and basal levels. ECV is significantly affected by HTN, DM, and eGFR, even in asymptomatic subjects.

Familial risk of dilated and hypertrophic cardiomyopathy: a national family study in Sweden

AIMS

This study aims to determine the familial incidence of dilated (DCM) and hypertrophic cardiomyopathy (HCM) in first-degree, second-degree, and third-degree relatives of affected individuals.

METHODS AND RESULTS

In this population-based multigenerational cohort study, full-siblings, half-siblings, and cousin pairs born to Swedish parents between 1932 and 2015 were included, and register-based DCM and HCM diagnoses among relatives were ascertained. Adjusted odds ratios (ORs) for DCM and HCM were calculated for relatives of individuals with DCM and HCM compared with relatives of individuals without DCM and HCM for reference. Total study population included 6 334 979 subjects and consisted of 5 577 449 full-siblings, 1 321 414 half-siblings, and 3 952 137 cousins. Overall, 10 272 (0.16%) unique individuals were diagnosed with DCM and 3769 (0.06%) with HCM. Of these, 7716 (75.12%) and 2375 (63.01%) were males, respectively. Familial risk ORs for DCM were 5.35 [95% confidence intervals (CI): 4.85-5.90] for full-siblings, 2.68 (95% CI:1.86-3.87) for half-siblings, and 1.72 (95% CI:1.12-2.64) for cousins of affected individuals. The ORs for HCM were 42.44 (95% CI:37.66-47.82) for full-siblings, 32.70 (95% CI:21.32-50.15) for half-siblings, and 36.96 (95% CI:29.50-46.31) for cousins of affected individuals. In sex-stratified analysis, relatives of affected females were found more likely to be affected than were relatives of affected males, with stronger aggregation observed for HCM.

CONCLUSIONS

Familial risk of HCM and DCM is high and associated with genetic resemblance, with strongest aggregations observed in relatives of affected females with HCM, whereas this association was distinctly attenuated for DCM. The finding of a Carter effect, more pronounced in HCM, suggests a multifactorial threshold model of inheritance.

Automated Classification of Left Ventricular Hypertrophy on Cardiac MRI

Left ventricular hypertrophy is an independent predictor of coronary artery disease, stroke, and heart failure. Our aim was to detect LVH cardiac magnetic resonance (CMR) scans with automatic methods. We developed an ensemble model based on a three-dimensional version of ResNet. The input of the network included short-axis and long-axis images. We also introduced a standardization methodology to unify the input images for noise reduction. The output of the network is the decision whether the patient has hypertrophy or not. We included 428 patients (mean age: 49 ± 18 years, 262 males) with LVH (346 hypertrophic cardiomyopathy, 45 cardiac amyloidosis, 11 Anderson–Fabry disease, 16 endomyocardial fibrosis, 10 aortic stenosis). Our control group consisted of 234 healthy subjects (mean age: 35 ± 15 years; 126 males) without any known cardiovascular diseases. The developed machine-learning-based model achieved a 92% F1-score and 97% recall on the hold-out dataset, which is comparable to the medical experts. Experiments showed that the standardization method was able to significantly boost the performance of the algorithm. The algorithm could improve the diagnostic accuracy, and it could open a new door to AI applications in CMR.

Friend or foe? Unraveling the complex roles of protein tyrosine phosphatases in cardiac disease and development

Regulation of protein tyrosine phosphorylation is critical for most, if not all, fundamental cellular processes. However, we still do not fully understand the complex and tissue-specific roles of protein tyrosine phosphatases in the normal heart or in cardiac pathology. This review compares and contrasts the various roles of protein tyrosine phosphatases known to date in the context of cardiac disease and development. In particular, it will be considered how specific protein tyrosine phosphatases control cardiac hypertrophy and cardiomyocyte contractility, how protein tyrosine phosphatases contribute to or ameliorate injury induced by ischaemia / reperfusion or hypoxia / reoxygenation, and how protein tyrosine phosphatases are involved in normal heart development and congenital heart disease. This review delves into the newest developments and current challenges in the field, and highlights knowledge gaps and emerging opportunities for future research.

Magnetic Resonance for Differential Diagnosis of Left Ventricular Hypertrophy: Diagnostic and Prognostic Implications

BACKGROUND

Left ventricular hypertrophy (LVH) may be due to different causes, ranging from benign secondary forms to severe cardiomyopathies. Transthoracic Echocardiography (TTE) and ECG are the first-level examinations for LVH diagnosis. Cardiac magnetic resonance (CMR) accurately defines LVH type, extent and severity.

OBJECTIVES

to evaluate the diagnostic and prognostic role of CMR in patients with TTE and/or ECG evidence of LVH.

METHODS

We performed CMR in 300 consecutive patients with echocardiographic and/or ECG signs of LVH.

RESULTS

Overall, 275 patients had TTE evidence of LVH, with initial suspicion of hypertrophic cardiomyopathy (HCM) in 132 (44%), cardiac amyloidosis in 41 (14%), hypertensive LVH in 48 (16%), aortic stenosis in 4 (1%), and undetermined LVH in 50 (16%). The initial echocardiographic diagnostic suspicion of LVH was confirmed in 172 patients (57.3%) and changed in 128 patients (42.7%, p < 0.0001): the diagnosis of HCM increased from 44% to 71% of patients; hypertensive and undetermined LVH decreased significantly (respectively to 4% and 5%). CMR allowed for a diagnosis in 41 out of 50 (82%) patients with undetermined LVH at TTE. CMR also identified HCM in 17 out of 25 patients with apparently normal echocardiography but with ECG criteria for LVH. Finally, the reclassification of the diagnosis by CMR was associated with a change in survival risk of patients: after CMR reclassification, no events occurred in patients with undetermined or hypertensive LVH.

CONCLUSIONS

CMR changed echocardiographic suspicion in almost half of patients with LVH. In the subgroup of patients with abnormal ECG, CMR identified LVH (particularly HCM) in 80% of patients. This study highlights the indication of CMR to better characterize the type, extent and severity of LVH detected at echocardiography and suspected with ECG.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Cardiac magnetic resonance in the assessment of hypertrophic cardiomyopathy phenotypes and stages - pictorial review

The aim of this paper is to present recent advances in hypertrophic cardiomyopathy (HCM) diagnosis and treatment based on a literature review. Special emphasis has been placed on the role of cardiac magnetic resonance imaging (CMR) for the assessment of morphological and functional consequences of different stages of HCM including prognostication. The text is illustrated with the images and data of the HCM patients diagnosed with CMR study in our hospital. CMR is an important tool, particularly relevant in novel risk factors and LV dysfunction groups. The HCM group with overt left ventricular dysfunction is underrecognized, often labelled by clinicians as dilated cardiomyopathy. Advanced diagnostic and management strategies effectively influence the natural history of HCM.

Perioperative Amiodarone to Prevent Atrial fibrillation after Septal Myectomy in obstrUctive hypeRtroPHic cardiomyopathy

Aims

Amiodarone reduces the incidence of atrial fibrillation (AF) following coronary artery bypass surgery; however, the benefit of perioperative amiodarone in patients undergoing septal myectomy (SM) for obstructive hypertrophic cardiomyopathy (oHCM) has not been studied. We hypothesized that prophylactic amiodarone would reduce the incidence of postoperative AF (POAF) following SM for oHCM.

Methods and Results

A single‐centre, pre‐post intervention open‐label study of oral amiodarone (200 mg twice daily starting 7 days preoperatively and 200 mg once daily continuing for 30 days postoperatively) in patients without prior AF undergoing SM for oHCM from 2014 to 2018. The primary outcome was incident AF within 30 days. Secondary outcomes were unplanned readmission, AF treatment, total and intensive care unit (ICU) length of stay (LOS), and pacemaker implantation for high‐grade atrioventricular (AV) block. 61 patients met inclusion criteria with 34 (55.8%) in the pre‐intervention (control) group and 27 (44.2%) in the post‐intervention (amiodarone) group. The incidence of POAF was 11.0% in the amiodarone group compared with 38.2% in the control group (P = 0.017). After adjusting for age, amiodarone was associated with less POAF [adjusted odds ratio (aOR) 0.21; 95% confidence interval (CI) 0.05, 0.76; P = 0.016]. ICU (2 days [IQR 1, 4] vs. 3 days [IQR 2, 4]; P = 0.165) and total (6 days [IQR 5, 6] vs. 6 days [IQR 5, 7]; P = 0.165) LOS were similar, as was the rate of pacemaker implantation (7.4% vs. 8.3%, P > 0.999). There were no adverse events associated with amiodarone.

Conclusions

Perioperative oral amiodarone is safe and was associated with lower incidence of POAF following SM for oHCM.

The Feline Cardiomyopathies: 1. General concepts

PRACTICAL RELEVANCE

The feline cardiomyopathies are the most prevalent type of heart disease in adult domestic cats. Several forms have been identified (see Parts 2 and 3), with hypertrophic cardiomyopathy (HCM) being the most common. Clinically the cardiomyopathies are often indistinguishable. Cats with subclinical cardiomyopathy may or may not have characteristic physical examination findings (eg, heart murmur, gallop sound), or radiographic cardiomegaly. Cats with severe disease may develop signs of heart failure (eg, dyspnea, tachypnea) or systemic arterial thromboembolism (ATE; eg, pain and paralysis). Sudden death is possible. Treatment usually does not alter the progression from subclinical to clinical disease and often the treatment approach, once clinical signs are apparent, is the same regardless of the type of cardiomyopathy. However, differentiating cardiomyopathy from normal variation may be important prognostically.

PATIENT GROUP

Domestic cats of any age from 3 months upward, of either sex and of any breed, can be affected. Mixed-breed cats are most commonly affected but certain breeds are disproportionately prone to developing HCM.

DIAGNOSTICS

Subclinical feline cardiomyopathies may be suspected based on physical examination findings, thoracic radiographs and cardiac biomarker results but often the disease is clinically silent. The definitive clinical confirmatory test is echocardiography. Left heart failure (pulmonary edema and/or pleural effusion) is most commonly diagnosed radiographically, but point-of-care ultrasound and amino terminal pro-B-type natriuretic peptide (NT-proBNP) biomarker testing can also be useful, especially when the stress of taking radiographs is best avoided.

KEY FINDINGS

Knowledge of pathophysiological mechanisms helps the practitioner identify the feline cardiomyopathies and understand how these diseases progress and how they manifest clinically (heart failure, ATE). Existing diagnostic tests have strengths and limitations, and being aware of these can help a practitioner deliver optimal recommendations regarding referral.

CONCLUSIONS

Several types of feline cardiomyopathies exist in both subclinical (mild to severe disease) and clinical (severe disease) phases. Heart failure and ATE are the most common clinical manifestations of severe cardiomyopathy and are therapeutic targets regardless of the type of cardiomyopathy. The long-term prognosis is often guarded or poor once overt clinical manifestations are present.

AREAS OF UNCERTAINTY

Some cats with presumed cardiomyopathy do not have echocardiographic features that fit the classic cardiomyopathies (cardiomyopathy - nonspecific phenotype). Although no definitive treatment is usually available, understanding how cardiomyopathies evolve remains worthy of investigation.

Purkinje triggers of ventricular fibrillation in patients with hypertrophic cardiomyopathy

INTRODUCTION

Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). The origin of VF and the success of catheter ablation to eliminate recurrent episodes in this population are poorly understood.

METHODS AND RESULTS

From 2010 to 2014, five patients with HCM (age 21 ± 9 years, three female) underwent invasive electrophysiological studies and ablation at our center after resuscitation from recurrent (9 ± 7) episodes of VF. Ventricular premature beats (VPBs), seen to initiate VF in certain cases, were recorded noninvasively before the ablation procedure. Postprocedural computed tomography (CT) was performed to correlate ablation sites with myocardial hypertrophy in three patients. Outcomes were assessed by clinical follow-up and implantable cardioverter-defibrillator interrogations. VPB triggers were localized invasively to the distal left Purkinje conduction system (left posterior fascicle [2], left anterior fascicle [1], and both fascicles [2]). All targeted VF triggers were successfully eliminated by radiofrequency ablation in the left ventricle. Among patients with postablation CT imaging, 93 ± 12% of ablation sites corresponded to hypertrophied segments. Over 50 ± 38 months, four of five patients were free from primary VF without antiarrhythmic drug therapy. One patient who had 13 episodes of VF before ablation had a single recurrence.

CONCLUSION

In our study of patients with HCM and recurrent VF, VF was not initiated from the myocardium but rather from Purkinje arborization. These sources colocalized with the hypertrophic substrate, suggesting electromechanical interaction. Focal ablation at these sites was associated with a marked reduction in VF burden.

Interactions of hypertension, obesity, left ventricular hypertrophy, and heart failure

PURPOSE OF REVIEW

Hypertension (HTN) and obesity are major risk factors for cardiac remodeling and dysfunction, leading to left ventricular hypertrophy (LVH) and heart failure (HF). In this review, we discuss the complex mechanisms and effects of HTN and obesity, and their treatments in LVH, ventricular function, and HF.

RECENT FINDINGS

Obesity and HTN impact the heart through overlapping neurohormonal pathways. However, the relationship between obesity and cardiomyopathy is more complex, and additional metabolic and hemodynamic pathways seem to contribute to cardiac dysfunction in these patients. Weight loss and blood pressure (BP) control help to prevent and reverse at least some of the damage caused by obesity and HTN even beyond what would be expected from solely the hemodynamic changes.

SUMMARY

Obesity and HTN cause maladaptive changes in the heart that can lead to LVH and HF. Weight loss and BP control help to, at least partially, reverse some of these changes and improve clinical outcomes in patients with HF.

Transthoracic echocardiography of hypertrophic cardiomyopathy in adults: a practical guideline from the British Society of Echocardiography

Hypertrophic cardiomyopathy (HCM) is common, inherited and characterised by unexplained thickening of the myocardium. The British Society of Echocardiography (BSE) has recently published a minimum dataset for transthoracic echocardiography detailing the core views needed for a standard echocardiogram. For patients with confirmed or suspected HCM, additional views and measurements are necessary. This guideline, therefore, supplements the minimum dataset and describes a tailored, stepwise approach to the echocardiographic examination, and echocardiography’s position in the diagnostic pathway, before advising on the imaging of disease complications and invasive treatments.

Myocardial Fibrosis in the Pathogenesis, Diagnosis, and Treatment of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a type of hereditary cardiomyopathy caused by gene mutation. Its histological features include cardiomyocyte hypertrophy and disarray as well as myocardial fibrosis. Gene mutation, abnormal signal transduction, and abnormal energy metabolism are considered the main mechanisms of myocardial fibrosis. There is a strong correlation between myocardial fibrosis and the occurrence, development, and prognosis of HCM. We review the application of myocardial fibrosis in the diagnosis and treatment of HCM, focusing on research progress and the application of magnetic resonance imaging on the basis of the characteristics of fibrosis in the diagnosis and prognosis of HCM.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Is Masked Hypertension an underlying Cause of Unexplained Left Ventricle Hypertrophy?

OBJECTIVES

Unexplained left ventricular hypertrophy (ULVH) is defined as increased wall thickness in the absence of conditions that predispose to hypertrophy. The aim of this study was to evaluate the rate of masked hypertension in patient with unexplained left ventricle hypertrophy.

METHOD

A total of 120 consecutive unexplained left ventricle hypertrophy patients without overt hypertension and diabetes and 121 healthy control subjects were included in the study. After a complete medical history and laboratory examination, patients' height, weight, waist circumference heart rate, and office blood pressure were recorded. All subjects underwent ambulatory blood pressure monitoring, and transthoracic echocardiography.

RESULTS

Mean age were similar between patients with ULVH and controls. There was no significant difference in total cholesterol, HDL, LDL cholesterol and triglyceride levels, left ventricle ejection fraction, between the groups. Prevalence of Masked hypertension was significantly higher in patients with ULVH than controls (28.3% vs 6.6%, p < .001). Left ventricular mass index (141.9 ± 16.8 g/cm² vs. 67.3 ± 10.3 g/cm², p < .001) was significantly higher in masked hypertensive patients with ULVH compared to normotensive ULVH and control subjects.

CONCLUSION

In this study, we found high prevalence of masked hypertension in ULVH patients. Patients with ULVH should be screened by ABPM to detect possible masked hypertension.

Prevalence of Unexplained Left Ventricular Hypertrophy by Cardiac Magnetic Resonance Imaging in MESA

Background

Hypertrophic cardiomyopathy is defined as unexplained left ventricular (LV) hypertrophy (wall thickness ≥15 mm) and is prevalent in 0.2% of adults (1:500) in population‐based studies using echocardiography. Cardiac magnetic resonance imaging (MRI) allows for more accurate wall thickness measurement across the entire ventricle than echocardiography. The prevalence of unexplained LV hypertrophy by cardiac MRI is unknown. MESA (Multi‐Ethnic Study of Atherosclerosis) recruited individuals without overt cardiovascular disease 45 to 84 years of age.

Methods and Results

We studied 4972 individuals who underwent measurement of regional LV wall thickness by cardiac MRI as part of the MESA baseline exam. American Heart Association criteria were used to define LV segments. We excluded participants with hypertension, LV dilation (≥95% predicted end‐diastolic volume) or dysfunction (ejection fraction ≤50%), moderate‐to‐severe left‐sided valve lesions by cardiac MRI, severe aortic valve calcification by cardiac computed tomography (aortic valve Agatston calcium score >1200 in women or >2000 in men), obesity (body mass index >35 kg/m²), diabetes mellitus, and current smoking. Sixty‐seven participants (aged 64±10 years, 9% female) had unexplained LV hypertrophy (wall thickness ≥15 mm in at least 2 adjacent LV segments), representing 1.4% (1 in 74) participants, 2.6% of men and 0.2% of women. Prevalence was similar across categories of race/ethnicity. Hypertrophy was focal in 17 (25.4%), intermediate in 44 (65.7%), and diffuse in 5 (7.5%) participants.

Conclusions

The prevalence of unexplained LV hypertrophy in a population‐based cohort using cardiac MRI was 1.4%. This may have implications for the diagnosis of patients with hypertrophic cardiomyopathy and will require further study.

Phenotypes of hypertrophic cardiomyopathy: genetics, clinics, and modular imaging

Hypertrophic cardiomyopathy (HCM) is the most common cardiovascular disease with genetic transmission, characterized by the hypertrophy of any segment of the left ventricle (LV), not totally explained by improper loading conditions, with LV systolic function preserved, increased, or reduced. The histopathological mechanism involved in HCM refers to the primary injury of the myocardium, as follows: disorganized array of myocytes, extracellular matrix modification, microvascular dysfunction, with subsequent appearance of myocardial fibrosis. Multiple sarcomere proteins mutations are responsible for HCM, but two of them are involved in 70% of the cases of HCM: β-myosin heavy chain (MYH7) and myosin-binding protein C (MYBPC3). The development of new genetic techniques involving genome editing is promising to discover a gene therapy for patients with HCM. Clinical presentation may differ from asymptomatic to sudden cardiac death (SCD), the last one targeting younger adults. In this case, the diagnosis and evaluation of SCD risk factors is extremely important. The common method of diagnosis is transthoracic echocardiography, but cardiac magnetic resonance (CMR) imaging represents "gold standard" in the evaluation of HCM patients. Treatment includes pharmacological therapy, surgery, alcohol ablation, and not least SCD prevention.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.